Rotatable knob interface

ABSTRACT

A method of detecting shift of a rotatable interface is disclosed. The rotatable interface has a fixed base with a conductive region on a bottom surface, the fixed base attached to a display screen of an input device. The method includes providing, during a first time period, a reference signal to first and second sets of electrodes of the input device that are each capacitively coupled to the conductive region. The method further includes, during a second time period, providing the reference signal to the first set of electrodes, providing a sensing signal to the second set of electrodes, and receiving, during the second time period, a resulting signal on the second set of electrodes. The method still further includes determining a translation of the rotatable interface relative to the display screen based, at least in part, on the resulting signal values received during the second time period.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/142,667, filed Jan. 6, 2021, the disclosure of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

Embodiments of this disclosure relate to a rotatable knob interface.

BACKGROUND

Input devices including proximity sensor devices may be used in avariety of electronic systems. A proximity sensor device may include asensing region, demarked by a surface, in which the proximity sensordevice determines the presence, location, force and/or motion of one ormore input objects. Proximity sensor devices may be used to provideinterfaces for the electronic systems. For example, proximity sensordevices may be used as input devices for larger computing systems, suchas touchpads integrated in, or peripheral to, notebook or desktopcomputers. Proximity sensor devices may also often be used in smallercomputing systems, such as touch screens integrated in cellular phones.Additionally, proximity sensor devices may be implemented as part of amulti-media entertainment system or an automobile. In such cases, it isuseful to interface a knob to a proximity sensor device.

SUMMARY

This Summary is provided to introduce in a simplified form a selectionof concepts that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tolimit the scope of the claimed subject matter.

A sensing system includes a display panel comprising sensor electrodes,and a processing system coupled to the sensor electrodes. The processingsystem is configured to operate, during a first period, a first subsetof the sensor electrodes for input sensing by driving the first subsetwith a reference signal, and to operate, during the first period, asecond subset of the sensor electrodes for input sensing by driving thesecond subset with the reference signal. The processing system isfurther configured to operate, during a second period, the first subsetof the sensor electrodes for shift detection by driving the first subsetof the sensor electrodes with a sensing signal and receiving resultingsignals from the first subset of the sensor electrodes, drive, duringthe second period, the second subset of the sensor electrodes with thereference signal. The sensing system further includes an electronicdevice disposed over the display panel, the electronic device includinga conductive region configured to couple to each of the first subset ofthe sensor electrodes and the second subset of the sensor electrodes,wherein the resulting signals received from the first subset of sensorelectrodes during the second period are affected based on the positionof the conductive region relative to the display panel. The processingsystem is further configured to, based on the resulting signals,determine a shift of the electronic device relative to the displaypanel.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate only someembodiments of this disclosure and are therefore not to be consideredlimiting of its scope, for the disclosure may admit to other equallyeffective embodiments.

FIG. 1 illustrates an example input device with a rotatable knobinterface, according to one or more embodiments.

FIG. 2 illustrates a cross-sectional side view of an example rotatableknob interface, according to one or more embodiments.

FIG. 3 illustrates an exploded view of the example rotatable knobinterface of FIG. 2.

FIG. 4A illustrates an underside view of the fixed base of an examplerotatable knob interface as shown in FIG. 3 with a first set ofreference electrodes, and two sets of coupling electrodes according toone or more embodiments.

FIG. 4B illustrates an example portion of an input device illustrating agrid of sensor electrodes, the grid of sensor electrodes configured intotwo sets of sensor electrodes, according to one or more embodiments.

FIG. 4C illustrates the fixed base of an example rotatable knobinterface of FIG. 4A as positioned over the example grid of sensorelectrodes of FIG. 4B, according to one or more embodiments.

FIG. 5 illustrates a perspective top view, a bottom view and a top viewof the example fixed base of FIGS. 3 and 4A through 4C, according to oneor more embodiments.

FIG. 6A illustrates exploded and collapsed views of the example fixedbase and example plastic bearings shown in FIG. 3.

FIG. 6B illustrates the respective exploded and collapsed views shown inFIG. 6A, with the addition of the example rotary wheel of FIG. 3provided on top of an example flat ring-shaped bearing.

FIG. 7A illustrates a detailed bottom view of the rotary wheel of FIG.3, according to one or more embodiments.

FIG. 7B illustrates a detailed top view of the rotary wheel of FIG. 7A,according to one or more embodiments.

FIG. 8 depicts the top view of the example fixed base, and the bottomview of the example rotary wheel, as shown in FIGS. 5 and 7A,respectively, and capacitive coupling between them, according to one ormore embodiments.

FIG. 9A depicts an underside of an alternate fixed base, according toone or more embodiments.

FIG. 9B depicts a top view of the alternate fixed base of FIG. 11Aaccording to one or more embodiments.

FIG. 10 illustrates a bottom view of an example fixed base with outlinesaround regions to be attached with a conductive adhesive, according toone or more embodiments.

FIG. 11 depicts an example conductive structure that may be used inplace of a rotary wheel and thin bearing, according to one or moreembodiments.

FIG. 12A illustrates, from a view underneath the display panel, a fullygrounded set of grounding pads provided underneath a conductive regionon the underside of a fixed base bottom, according to one or moreembodiments.

FIG. 12B illustrates half of the pixels under the conductive regionshown in FIG. 15A being driven by a sensing waveform during apre-defined time interval, according to a knob shift detection method,according to one or more embodiments.

FIG. 13 illustrates the apparatus of FIG. 12B, where a subset of pixelsprovided underneath a conductive region of a rotatable knob base bottombeing driven by a sensing waveform, according to an example alternateknob shift detection method, according to one or more embodiments.

FIG. 14 illustrates an example method for implementing a rotatable knobinterface on an example input device, according to one or moreembodiments.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe Figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation. The drawings should not be understood as beingdrawn to scale unless specifically noted. Also, the drawings may besimplified and details or components omitted for clarity of presentationand explanation. The drawings and discussion serve to explain principlesdiscussed below, where like designations denote like elements.

DETAILED DESCRIPTION

The following description may use perspective-based descriptions such astop/bottom, in/out, over/under, and the like. Such descriptions aremerely used to facilitate the discussion and are not intended torestrict the application of embodiments described herein to anyparticular orientation.

The following description may use the phrases “in one embodiment,” or“in one or more embodiments,” or “in some embodiments”, which may eachrefer to one or more of the same or different embodiments. Furthermore,the terms “comprising,” “including,” “having,” and the like, as usedwith respect to embodiments of the present disclosure, are synonymous.

The terms “coupled with,” along with its derivatives, and “connected to”along with its derivatives, may be used herein, including in the claims.“Coupled” or “connected” may mean one or more of the following.“Coupled” or “connected” may mean that two or more elements are indirect physical or electrical contact. However, “coupled” or “connected”may also mean that two or more elements indirectly contact each other,but yet still cooperate or interact with each other, and may mean thatone or more other elements are coupled or connected between the elementsthat are said to be coupled with or connected to each other. The term“directly coupled” or “directly connected” may mean that two or elementsare in direct contact.

As used herein, including in the claims, the term “circuitry” may referto, be part of, or include an Application Specific Integrated Circuit(ASIC), an electronic circuit, a processor (shared, dedicated, or group)and/or memory (shared, dedicated, or group) that execute one or moresoftware or firmware programs, a combinational logic circuit, and/orother suitable components that provide the described functionality.

FIG. 1 is a block diagram of an exemplary electronic device 100 (e.g.,an input device or system), in accordance with embodiments of thedisclosure. The electronic device 100 may be configured to provide inputto an electronic system (not shown), and/or to update one or moredevices. As used in this document, the term “electronic system” (or“electronic device”) broadly refers to any system capable ofelectronically processing information. Some non-limiting examples ofelectronic systems include personal computers of all sizes and shapes,such as desktop computers, laptop computers, netbook computers, tablets,web browsers, e-book readers, and personal digital assistants (PDAs).Additional example electronic systems include composite input devices,such as physical keyboards that include the electronic device 100 andseparate joysticks or key switches. Further example electronic systemsinclude peripherals such as data input devices (including remotecontrols and mice), and data output devices (including display screensand printers). Other examples include remote terminals, kiosks, andvideo game machines (e.g., video game consoles, portable gaming devices,and the like). Other examples include communication devices (includingcellular phones, such as smart phones), and media devices (includingrecorders, editors, and players such as televisions, set-top boxes,music players, digital photo frames, and digital cameras). Additionally,the electronic system could be a host or a slave to the input device. Inother embodiments, the electronics system may be part of an automobile,and the electronic device 100 represents one or more sensing devices ofthe automobile. For example, the electronic device 100 is part of amultimedia entertainment system of an automobile. In one embodiment, anautomobile may include multiple electronic devices 100, where eachelectronic device 100 may be configured differently than the other.

The electronic device 100 can be implemented as a physical part of theelectronic system, or can be physically separate from the electronicsystem. As appropriate, the electronic device 100 may communicate withparts of the electronic system using any one or more of the following:buses, networks, and other wired or wireless interconnections. Examplecommunication protocols include Inter-Integrated Circuit (I²C), SerialPeripheral Interface (SPI), Personal System/2 (PS/2), Universal SerialBus (USB), Bluetooth®, Radio Frequency (RF), and Infrared DataAssociation (IrDA) communication protocols.

The electronic device 100 may utilize any combination of sensorcomponents and sensing technologies to detect user input. For example,as illustrated in FIG. 1, the electronic device 100 comprises one ormore sensor electrodes 125 that may be driven to detect objects and/orupdate one or more devices. The sensor electrodes 125 may be part of acapacitive sensing device. In other embodiments, the sensor electrodes125 are part of an image sensing device, radar sensing device, orultrasonic sensing device, among others. In one embodiment, the sensorelectrodes 125 are discrete sensor electrodes.

In one embodiment, the electronic device 100 includes the display panel120. In such embodiments, the sensor electrodes 125 are comprised ofdisplay electrodes of the display panel 120. For example, the sensorelectrodes 125 are comprised of the common voltage electrodes, datalines, or gate lines of the display panel 120. In such embodiments, thesensor electrodes 125 are operated for input sensing and for updatingthe display of the display panel 120. For example, the sensor electrodes125 function as the reference voltage electrode of the display panel120.

Some of the examples described herein include a matrix sensor inputdevice. In such examples, as is illustrated in FIG. 1, the sensorelectrodes 125 are disposed in a two dimensional array of rows andcolumns. Further, as described in detail below, electronic device 100includes a rotatable knob interface 150 that interacts with one or moreof the sensor electrodes 125.

The sensor electrodes 125 may have a similar size and shape. Forexample, as illustrated in FIG. 1, each of the sensor electrodes 125 issubstantially rectangular in shape. In other embodiments, at least onesensor electrode 125 has a different shape and/or size than another atleast one sensor electrode 125. For example, the sensor electrodes 125may be diamond shaped, circular in shape, have interdigitated fingers toincrease field coupling, and/or have floating cut-outs inside to reducestray capacitance to nearby electrical conductors. Further, theorientation of the sensor electrodes 125 may differ from thatillustrated in FIG. 1.

The sensor electrodes 125 may be disposed in a common layer. Forexample, the sensor electrodes 125 are disposed on a common side of asubstrate. The sensor electrodes 125 may be disposed on lens orencapsulation layer of the display panel 120, or a substrate attached tothe display panel 120. In other embodiments, a first one or more of thesensor electrodes 125 is disposed in a first layer and a second one ormore of the sensor electrodes 125 is disposed in a second layer. Forexample, a first one or more of the sensor electrodes 125 is disposed ona first side of a first substrate, and a second one or more of thesensor electrodes 125 is disposed on a second side of the firstsubstrate. In other embodiments, a first one or more of the sensorelectrodes 125 is disposed on a first substrate, and a second one ormore of the sensor electrodes 125 is disposed on a second substrate.

Some capacitive implementations utilize “self-capacitance” (or “absolutecapacitance”) sensing methods based on changes in the capacitivecoupling between sensor electrodes and one or more input objects. Invarious embodiments, an input object near the sensor electrodes, suchas, for example, input object 145 (e.g., a digit or stylus), alters theelectric field near the sensor electrodes 125, thus changing themeasured capacitive coupling. In one implementation, an absolutecapacitance sensing method operates by modulating sensor electrodes 125with respect to a reference voltage (e.g., system ground), and bydetecting the capacitive coupling between the sensor electrodes andinput objects. For example, a resulting signal is received from themodulated sensor electrode or electrodes 125. Modulating the sensorelectrodes 125 with respect to a reference voltage includes driving thesensor electrodes 125 with a sensing signal. When operating the sensorelectrodes 125 for absolute capacitive sensing, the sensing signal isreferred to as an absolute capacitive sensing signal. In suchembodiments, the resulting signal comprises effect(s) corresponding tothe absolute capacitive sensing signal, and/or to one or more sources ofenvironmental interference (e.g., other electromagnetic signals). Theabsolute capacitive sensing signal has a varying voltage. Further, theabsolute capacitive sensing signal is a periodic or aperiodic signal.The absolute capacitive sensing signal has a square waveform,trapezoidal waveform, sinusoidal waveform, or a sawtooth waveform, amongothers.

Some capacitive implementations utilize “mutual capacitance” (or“transcapacitance”) sensing methods based on changes in the capacitivecoupling between two or more of the sensor electrodes 125. An inputobject (e.g., the input object 145) near the sensor electrodes 125alters the electric field between the sensor electrodes, thus changingthe measured capacitive coupling. In one implementation, atranscapacitive sensing method operates by detecting the capacitivecoupling between one or more transmitter sensor electrodes (also“transmitter electrodes” or “transmitters”) and one or more receiversensor electrodes (also “receiver electrodes” or “receivers”).Transmitter sensor electrodes may be modulated relative to a referencevoltage (e.g., system ground) to transmit transmitter signals. Forexample, the transmitter sensor electrodes are driven with a sensingsignal. In such embodiments, the sensing signal is referred to as atranscapacitive sensing signal. The transcapacitive sensing signal has avarying voltage. Further, the transcapacitive sensing signal is aperiodic or aperiodic signal. The transcapacitive sensing signal has asquare waveform, trapezoidal waveform, sinusoidal waveform, or asawtooth waveform, among others.

Receiver sensor electrodes may be held substantially constant relativeto the reference voltage, or modulated with reference to the transmittersensor electrodes to facilitate receipt of resulting signals. Aresulting signal may comprise effect(s) corresponding to one or moretranscapacitive sensing signals, and/or to one or more sources ofenvironmental interference (e.g., other electromagnetic signals). Sensorelectrodes may be dedicated transmitters or receivers, or may beconfigured to both transmit and receive.

Capacitive sensing devices may be used for detecting presence and/orposition of input objects (e.g., the input object 145) in proximity toand/or touching input sensing regions of an input device. Further,capacitive sensing devices may be used to sense features of an inputobject, such as a fingerprint. Still further, as in the example of FIG.1, in one or more embodiments, capacitive sensing devices may beprovided with a rotatable knob interface 150 that is electricallycoupled to the sensor electrodes 125. The sensor electrodes 125 may beconfigured to sense the rotary position of the rotatable knob interface150. For example, the rotatable knob interface 150 may have a homeposition and a compressed position, and the sensor electrodes 125 may beused to determine when the rotatable knob interface 150 is in the homeposition or the compressed position based on a change in capacitivecoupling of one or more of sensor electrodes 125 with one or morecoupling electrodes of the rotatable knob interface 150.

Continuing with reference to FIG. 1, a processing system 110 is shown aspart of the electronic device 100. The processing system 110 isconfigured to operate hardware of the electronic device 100.

The processing system 110 may also comprise electronically-readableinstructions, such as firmware code, software code, and/or the like.Components composing the processing system 110 may be located together,such as, for example, near the sensor electrodes 125. Components of theprocessing system 110 may be physically separate from one or morecomponents in proximity to the sensor electrodes 125 or one or morecomponents elsewhere. For example, the electronic device 100 may be aperipheral coupled to a desktop computer, and the processing system 110may comprise software configured to run on a central processing unit(CPU) of the desktop computer and one or more integrated circuits (ICs)(perhaps with associated firmware) separate from the CPU. As anotherexample, the electronic device 100 may be physically integrated in aphone, and the processing system 110 may comprise circuits and firmwarethat are part of a main processor of the phone. Further yet, theprocessing system 110 may be implemented within an automobile, and theprocessing system 110 may comprise circuits and firmware that are partof one or more of the electronic control units (ECUs) of the automobile.The processing system 110 is dedicated to implementing the electronicdevice 100. The processing system 110 may also perform other functions,such as operating display screens, driving haptic actuators, etc.

As illustrated in FIG. 1, the processing system 110 comprises a sensordriver 140. The sensor driver 140 generates the sensing signals, anddrives the sensor electrodes 125 with the sensing signals. Further, thesensor driver 140 may be configured to receive resulting signals fromthe sensor electrodes 125. The processing system 110 comprises parts ofor all of one or more integrated circuits (ICs) and/or other circuitrycomponents. The sensor driver 140 includes circuitry configured togenerate the sensing signal, drive the sensor electrodes with thesensing signals, and/or receive resulting signals from the sensorelectrodes 125. For example, the sensor driver 140 includes anoscillator, one or more current conveyers and/or a digital signalgenerator circuit. Further, the sensor driver 140 includes drivercircuitry including one or more amplifiers configured to drive thesensor electrodes 125 with the sensing signals. The sensor driver 140includes receiver circuitry including one or more analog front ends,filters, and demodulators to receive and process resulting signals.

In one embodiment, the sensor driver 140 may simultaneously operate twoor more of the sensor electrodes 125 for absolute capacitive sensing,such that a different resulting signal is simultaneously received fromeach of the sensor electrodes or a common resulting signal from two ormore sensor electrodes. In another embodiment, some of the sensorelectrodes 125 are operated for absolute capacitive sensing during afirst period and others of the sensor electrodes 125 are operated forabsolute capacitive sensing during a second period that isnon-overlapping with the first period.

As illustrated in FIG. 1, the processing system 110 includes thedetermination module 141. The determination module 141 comprisescircuitry, firmware, software, or a combination thereof. As will bedescribed in greater detail in the following, the determination module141 processes the resulting signals received by the sensor driver 140 todetermine changes in capacitive couplings of the sensor electrodes 125.For example, the determination module 141 is configured to determinechanges in a capacitive coupling between each modulated sensor electrodeand an input object, such as input objects 145, from the resultingsignals.

In various embodiments, different combinations of drivers and modulesmay be used. For example, the processing system 110 may include one ormore drivers that operate hardware such as display screens. Further, theprocessing system 110 may include data processing modules for processingdata such as sensor signals and positional information, and/or reportingmodules for reporting information.

The processing system 110 may be implemented as an integrated circuit(IC) chip, or as one or more IC chips. In some embodiments, theprocessing system 110 may comprise a controller, or a portion of acontroller, of the electronic device 100.

The processing system 110 may include a display driver (not shown) thatis configured for updating a display of the display panel 120. In suchan example, the processing system 110 may be referred to as includingtouch and display driver integration (TDDI) technology. In suchembodiments, the processing system 110 may be implemented as a TDDI ICchip, or a portion of a TDDI IC chip.

In some embodiments, the processing system 110 responds to user input(or lack of user input) directly by causing one or more actions. Exampleactions include changing operation modes, as well as graphic userinterface (GUI) actions such as cursor movement, selection, menunavigation, and other functions. In some embodiments, the processingsystem 110 provides information about the input (or lack of input) tosome part of the electronic device 100 (e.g., to a central processingsystem of the electronic system that is separate from the processingsystem 110, if such a separate central processing system exists). Insome embodiments, some part of the electronic system processesinformation received from the processing system 110 to act on userinput, such as to facilitate a full range of actions, including modechanging actions and GUI actions. Further, in some embodiments, theprocessing system 110 is configured to identify one or more inputobjects 145, and/or a location of the input objects 145 within a sensingregion of the electronic device 100. In some embodiments the processingsystem 110 is configured to identify one or more rotational changes ofknob interface 150, or one or more changes of state of knob interface150, or both, and map those changes to an input action.

The processing system 110 operates the sensor electrodes 125 to produceelectrical signals (resulting signals) indicative of input (or lack ofinput) in a sensing region of the electronic device 100. The processingsystem 110 may perform any appropriate amount of processing on theelectrical signals in producing the information provided to theelectronic system. For example, the sensor driver 140 of the processingsystem 110 digitizes analog electrical signals obtained from sensorelectrodes 125. As another example, the sensor driver 140 of theprocessing system 110 performs filtering or other signal conditioning.Further, the determination module 141 of the processing system 110subtracts or otherwise accounts for a baseline, such that theinformation reflects a difference between the electrical signals and thebaseline. The determination module 141 of the processing system 110further determines positional information, recognizes inputs ascommands, recognizes handwriting, recognizes fingerprint information,and/or distance to a target object, among others.

“Positional information” as used herein broadly encompasses absoluteposition, relative position, velocity, acceleration, and other types ofspatial information. Exemplary “zero-dimensional” positional informationincludes near/far or contact/no contact information. Exemplary“one-dimensional” positional information includes positions along anaxis. Exemplary “two-dimensional” positional information includesmotions in a plane. Exemplary “three-dimensional” positional informationincludes instantaneous or average velocities in space. Further examplesinclude other representations of spatial information. Historical dataregarding one or more types of positional information may also bedetermined and/or stored, including, for example, historical data thattracks position, motion, or instantaneous velocity over time.

It should be understood that while many embodiments of the disclosureare described in the context of a fully functioning apparatus, themechanisms of the present disclosure are capable of being distributed asa program product (e.g., software) in a variety of forms. For example,the mechanisms of the present disclosure may be implemented anddistributed as a software program on information bearing media that arereadable by electronic processors (e.g., non-transitorycomputer-readable and/or recordable/writable information bearing mediareadable by the processing system 110). Additionally, the embodiments ofthe present disclosure apply equally regardless of the particular typeof medium used to carry out the distribution. Examples ofnon-transitory, electronically readable media include various discs,memory sticks, memory cards, memory modules, and the like.Electronically readable media may be based on flash, optical, magnetic,holographic, or any other storage technology.

In embodiments where the sensor electrodes 125 are configured fordisplay updating and capacitive sensing, the processing system 110 maybe configured to generate a voltage signal to drive the sensorelectrodes 125 during a display update interval during which the displayof the display panel 120 is updated, and a sensing signal to drive thesensor electrodes 125 during an input sensing interval, respectively. Insuch embodiments, the voltage signal generated to drive the sensorelectrodes 125 during a display update interval may be a substantiallyconstant, or fixed voltage. The sensing signal generated to drive thesensor electrodes 125 during an input sensing interval may have avariable voltage. The value of a voltage signal to drive the sensorelectrodes 125 during a display update interval may be predetermined.For example, the voltage value may be provided by a manufacturer ofelectronic device 100 and/or the sensor electrodes 125, and may bedevice-specific to electronic device 100. The processing system 110 maycomprise circuitry to generate the voltage signal based on a clocksignal, the output of the oscillator and/or the corresponding value ofthe voltage signal.

The display of the display panel 120 is updated during display frames.During each display frame, one or more display lines of the display maybe updated. Multiple display update periods and non-display updateperiods may occur during each display frame of a plurality of displayframes. During a display update period, one or more of the displayelectrodes of the display panel 120 may be driven to update the displayof the display panel 120. During non-display update periods, one or moreof the display electrodes of the display panel 120 may not be driven toupdate the display of the display panel 120. The non-display updateperiods may occur between pairs of display update periods of a displayframe, at the start of a display frame, and/or at the end of a displayframe.

The display panel 120 includes one or more display lines. Each displayline corresponds to one or more subsets of the subpixels of the displaypanel 120. The one or more subsets may be connected to a common gateline of the display panel 120. Further, the subpixels may be updatedduring a common period. During each display update period, one or moredisplay lines of the display panel 120 may be updated. The displayframes may occur at a display frame rate. The display frame rate may be30 Hz, 60 Hz, 120 Hz, or 240 Hz, among others. The sensor driver 140 oranother driver of the processing system 110 may drive the displayelectrodes of the display panel 120 to update the display of the displaypanel.

The sensor driver 140 operates the sensor electrodes 125 for capacitivesensing during input sensing periods. The input sensing periods mayoccur during non-display update periods and/or display update periods.For example, one or more of the input sensing periods may be providedduring a non-display update period that occurs between two displayupdate periods of a display frame. In one embodiment, at least one inputsensing period is as long as a display update period. In one embodiment,at least one input sensing period is longer than a display updateperiod. In yet another embodiment, at least one input sensing period isthe same as a display update period.

Acquiring the resulting signals over successive input sensing periodsallows the rotation of the rotatable knob interface 150, as well aswhether the rotatable knob interface 150 is in the home state or thecompressed state, to be tracked.

As noted above, in one or more embodiments, an additional inputapparatus may be provided on top of the display panel 120 of theelectronic device 100, such as, for example, the rotatable knobinterface 150, and may be electrically coupled to some or all of thesensor electrodes 125 that are positioned near or below it. In one ormore embodiments, the additional input apparatus may provide alternateways for a user to provide input to electronic device 100 other thantouching, or hovering near, a display screen of the display panel 120with an input device 145. In the depicted example of FIG. 1, therotatable knob interface 150 is mounted onto the display panel 120, andmay have a full (as shown in FIG. 1) or partial overlap with the displaypanel 120. As noted, in one or more embodiments the rotatable knobinterface 150 may have a fixed base (not visible in the top view ofFIG. 1) that is provided with various sets of coupling electrodesconfigured to couple with respective sets of sensor electrodes 125, suchas one or more sets of the sensor electrodes 125 that are provided withsensing signals and one or more sets of electrodes that are providedwith reference signals. In one or more embodiments, the fixed base mayinclude different conductive regions respectively connected tocorresponding sets of coupling electrodes.

The rotatable knob interface 150 may also include a rotary wheel thatsits above, and rotates relative to, the fixed base. An underside of therotary wheel may be, for example, patterned with various conductive andnon-conductive regions, which may be configured to align with theconductive regions of the fixed base. Accordingly, there are variouselectrical couplings between the conductive regions of the fixed baseand the various conductive and non-conductive regions of the rotarywheel. These components may be further configured such that theseelectrical couplings change as the rotary wheel is rotated. By detectingthe effects of the changes in the electrical couplings by processing theresulting signals received on the display panel, the processing system110 determines an amount of rotation, or an amount of change inrotation, of the rotatable knob interface 150. In one embodiment, theconductive and non-conductive regions are disposed within a peripheralregion 152. In another embodiment, the various conductive andnon-conductive regions may be part of one or more rings of the rotarywheel. A first ring may be referred as an outer ring and may beconfigured for rough (or coarse) tuning of the rotatable knob interface150. A second ring may be referred to as an inner ring and may beconfigured for fine tuning of the rotatable knob interface 150. Thefirst ring is disposed outside the second ring.

The peripheral region 152 may have numerous possible examplearrangements of the conductive and non-conductive regions. Further,there may be various ways of having the rotary wheel and the fixed baseelectrically interact as the rotary wheel is rotated. Thus, alternateconfigurations and relative arrangements of both the conductive regionsof the fixed base, and the placement of the conductive andnon-conductive regions of the rotary wheel are possible, all beingwithin the scope of this disclosure.

The rotation imparted to the rotatable knob interface 150 by a user, ineither relative or absolute terms, may be detected by the electronicdevice 100. In one or more embodiments, the rotatable knob interface 150may also be pressed downwards by a user, and may thus have twopositions, a home, or “uncompressed” position, and a “compressed”position. The compressed position may be maintained by, for example,pushing down on the rotatable knob interface 150 against one or morebiasing springs. In one or more embodiments, the rotatable knobinterface 150 may have a cover. In alternate embodiments, the rotatableknob interface 150 may be pressed downwards so as to rest at multiplepositions, and thus may have multiple states between an “uncompressed”and a “fully compressed” position. In the home position the cover is ata greater distance above the rotary wheel than in a compressed position.

The rotary wheel may have several switches provided between the rotarywheel and the cover. These switches may include the biasing springs. Therotatable knob interface 150 may be provided with one or more couplingelectrodes 156 configured to couple to one or more of the sensorelectrodes 125 of the input device that are also driven with sensingsignals. In the example of FIG. 1, the coupling electrode 157 isconnected to an inner ring provided in the fixed base, which aligns witha similarly shaped inner ring 153 that is provided in the rotary wheel.When a user presses down on the cover of the rotatable knob interface,so that the rotatable knob interface 150 is then in the “compressed”position, the switches close. For example, closing the switches may bedefined as connecting the inner ring 153 of the rotary wheel with one ormore of the conductive regions provided in peripheral region 152. Thisserves to electrically couple the coupling electrode 157 of the fixedbase to coupling electrode 156 of the fixed base. The coupling electrode156 is coupled with one or more sensor electrodes 125 that are drivenwith a reference signal. However, when the user ceases to press down onthe cover, the coupling electrode 156 of the knob interface simplyelectrically floats. In various embodiments, direction and degree ofrotation, as well as a user pressing down on, or ceasing to press downupon, the rotatable knob interface 150, may be interpreted by processingsystem 110, such as, for example, by determination module 141, and maybe mapped to various user input actions, signals, or directives.

The rotatable knob interface 150 may be rotated in various ways. Forexample, the outer housing of the rotatable knob interface may begrabbed and turned, a top of the rotatable knob interface may be grabbedand turned, or a flange protruding from the side of the rotatable knobinterface may be grabbed and turned. Further, one or more fingertips maybe placed in on a recessed channel on an upper surface of the rotatableknob interface 150. Rotation of the rotatable knob interface 150 will bediscussed in more detail in the following.

As is discussed above, the electronic device 100 of FIG. 1 may beprovided in an automobile. For example, the display panel 120 may bevertically or horizontally oriented within a dashboard or center consoleof an automobile.

As illustrated in FIG. 1, one or more of the sensor electrodes 125 arenot physically blocked by the rotatable knob interface 150. Whileperforming capacitive sensing, the sensor electrodes 125 that are insideor are outside of region defined by the boundary 155 (described below),can both remain active. Thus, in such embodiments, both touches awayfrom the rotatable knob interface 150, and rotations of the rotatableknob interface 150, are detected and reported by the processing system110 at the same time.

In alternate embodiments, all other forms of user input besides thosereceived via the rotatable knob interface 150 may be disabled on theelectronic device. For example, the sensor electrodes 125 outside of theboundary 155 are not driven during the sensing interval to perform theircapacitive sensing. As a result, if an input object 145 is moved into,or away from, its vicinity, no resulting signal is obtained, or ifobtained, is not processed. This function may be implemented as a safetymeasure for example, to prevent a driver of an automobile frominteracting with the display panel 120 while driving, by allowing thedriver to only interact with the electronic device 100 via the rotatableknob interface 150. In such alternate embodiments, disabling of standardsensing functionality of one or more the sensor electrodes 125 may beimplemented during specified activities of the automobile, but notduring others. For example, the standard sensing functionality of one ormore of the sensor electrodes 125 may be disabled while the automobileis in actual motion. In this example, some of the sensor electrodes 125,for example, those not within specified proximity to the rotatable knobinterface 150 to cause interference with signals acquired from therotatable knob interface 150, may be operated normally to performstandard sensing, as described above. In some embodiments, one or moreof the sensor electrodes 125, for example those near or beneath therotatable knob interface 150, are disabled from performing capacitivesensing, while the remainder of the sensor electrodes 125 are operatedto perform capacitive sensing. In such embodiments, the disabled sensorelectrodes 125 may be selected based on their potential interference tothe resulting signals obtained from the sensor electrodes 125electrically coupled to the coupling electrodes of the rotatable knobinterface 150. As is illustrated in FIG. 1, the sensor electrodes 125within the region (area) defined by the boundary 155 may be referred toas being in a “blackout zone.” The sensor electrodes 125 within theblackout zone may not be operated to perform capacitive sensing during aperiod when the sensor electrodes 125 outside the region defined by theboundary 155 are operated normally to perform capacitive sensing. Aswill be described in greater detail in the following, one or more of thesensor electrodes 125 within the blackout zone and electrically coupledto the rotatable knob interface 150 are driven so as to capturerotations, compressions, and/or other motions of the rotatable knobinterface 150.

In the embodiments wherein all of the sensor electrodes 125 are disabledfrom standard sensing, pre-defined parameters may be used to provideinput to the electronic device 100 via the rotatable knob interface 150,for example, using a pre-defined set of rotations and/or pressings ofthe rotatable knob interface 150. The resulting signals modified by therotation and/or pressing are received by the processing system 110during an input sensing period, which then interprets the resultingsignals, for example, using determination module 141. The resultingsignals may be the same signal as the sensing signal that sensor driver140 drives the sensor electrode 125 with, after being modified by thecapacitive coupling of the rotatable knob interface 150.

In general, within the blackout zone (e.g., the region of sensorelectrodes 125 defined by the boundary 155), one or more of the sensorelectrodes 125 are coupled to respective coupling electrodes 156-159 ofthe underside of the fixed base of the rotatable knob interface 150. Insome embodiments, the coupling electrode 156 is driven with a referencesignal, and the coupling electrodes 157-159 are driven with a sensingsignal. Accordingly, a resulting signal modified by the relativerotational relationship of the fixed base and the rotary wheel of therotatable knob interface 150 is generated. The sensor electrodes withinthe blackout zone identified by the boundary 155 may be disabled fromstandard capacitive sensing at all times. For example, the sensorelectrodes within the blackout zone may perform capacitive sensingspecifically related to the rotatable knob interface 150, and the sensorelectrodes outside the blackout zone may perform capacitive sensing todetect one or more input objects 145 during normal operations.

The coupling electrodes 156-159 are illustrated in phantom as thecoupling electrodes 156-159 are occluded by the fixed base of therotatable knob interface 150. Further, the position and/or orientationof the coupling electrodes 156-159 with regard to the fixed base of therotatable knob interface 150 may vary from that illustrated in FIG. 1.For example, various embodiments related to the position and orientationof coupling electrodes of the rotatable knob interface 150 are describedin greater detail with regard to FIGS. 4A-4C.

As used herein, the term “disabled electrode” may refer to an electrodethat is not driven at all, an electrode that is driven with a guardsignal, or one that is driven with a constant voltage signal (e.g., adirect current (DC) voltage).

Continuing with reference to FIG. 1, as noted above, sets of sensorelectrodes 125 are electrically coupled to the coupling electrodes156-159 of the rotatable knob interface 150. Thus, during an inputsensing period a reference signal is supplied by the sensor driver 140to a first set of the sensor electrodes 125, and a sensing signal issupplied to second and third sets of the sensor electrodes 125. In oneor more embodiments, the reference signal may be a configurable DCoutput provided by the processing system 110. In some embodiments, theDC signal may be a ground signal of the electronic device 100. In someembodiments, a resulting signal is obtained from each of the second andthird sets of the sensor electrodes 125, where the resulting signals isthe sensing signal as modified by the rotational state and/orcompression state of the rotatable knob interface 150.

The resulting signals may be interpreted by the determination module 141to determine a rotation of the rotatable knob interface 150. In one ormore embodiments, the rotation may be determined in relative terms, suchas a differential angular change from a prior position, or in absoluteterms, such as a positive or negative angular change from a homeposition. In embodiments where the rotatable knob is turned more than360 degrees, the overall rotational distance may also be measured. Insuch embodiments, one or more user commands may be mapped to absoluterotational distance. The user commands may correspond to controlling agraphical user interface (GUI) of an input device. For example, the usercommands may include scrolling through a list of menu items presented onby the GUI. In alternate embodiments, only the one or both of overallangular change between starting position and ending position, or finalabsolute angular position, is measured. For example, the determinationmodule 141 determines a final absolute angular position which may berelated to a menu item presented by a GUI of an input device.

FIG. 2 illustrates exemplary components of an example rotatable knobinterface (e.g., the rotatable knob interface 150 shown in FIG. 1). Withreference thereto, starting at the bottom of the example device, thereis shown a fixed base 231. In some embodiments, the fixed base 231 doesnot move as the example knob interface is rotated. For example, thefixed base 231 may be affixed by, e.g., an adhesive, to a surface, e.g.,a lens or encapsulation layer of the display panel 120 of electronicdevice 100. The fixed base 231 may be affixed in a temporary,semi-permanent or permanent manner, and may be placed thereon so as toalign with a grid of the sensor electrode 125 provided in the electronicdevice 100.

Provided above the fixed base 231 is a rotary wheel 230. The rotarywheel 230 turns as the rotatable knob interface 150 is rotated. Forexample, in response to the cover cap 215 being rotated, as is describedbelow. At an inner side of the rotary wheel 230 is provided a verticalring bearing 225. The vertical ring bearing 225 is non-conductive, andmay be made of plastic or another non-conductive material, for example.An outer region of the vertical ring bearing 225 may have the shape of aring. Further, the body of vertical ring bearing 225 may have asubstantially tubular shape. Not shown in FIG. 2, but described belowwith reference to FIG. 3, is an additional substantially horizontalring-shaped bearing upon which the rotary wheel 230 sits, according toone or more embodiments. By using both of the bearings, frictionalforces between the fixed base 231, and the rotary wheel 230 may bereduced.

Continuing with reference to FIG. 2, provided on top of rotary wheel 230are one or more switches 220. For example, switches 220 may be acombinations of dome switches, capacitive switches, and/or othersuitable type of switches. There may be three switches 220, and theswitches may be equidistantly placed on an upper surface of rotary wheel230. In other embodiments, less than or more than three switches may beutilized. As described more fully below, in one or more embodiments, theswitches 220 are used to distinguish between two or more states of therotatable knob interface 150, namely a compressed state, in which theswitches 220 are closed, and an uncompressed state, in which theswitches 220 remain open. In other embodiments, the switches 220 may beused to distinguish more than two states of rotatable knob interface150. For example, the switches 220 may be used to distinguish acompressed, uncompressed state, and one or more partially compressedstates. In such embodiments, in the partially compressed states, theswitches 220 are neither opened nor fully closed. Partially compressed,compressed, and open states may be determined based on correspondingmeasured changes in capacitive coupling caused by movement of a couplingelectrode (e.g. the coupling electrode 157). In one embodiment, an openstate may correspond to a measured change in capacitive coupling thatcorresponds to a lowest value, a closed state may correspond to ameasured change in capacitive coupling that corresponds to a highestvalue, and a partially compressed state correspond to a measured changein capacitive coupling that corresponds to a value between the lowestvalue and the highest value. Multiple partially compressed states may beutilized. Each partially compressed state corresponds to a differentmeasured change in capacitive coupling. In one embodiment, thedetermination module 141 compares the measured change in capacitivecoupling to each of the values to determine the state of the rotatableknob interface 150. The compression state of the rotatable knobinterface 150 is orthogonal to its internal rotational position. Thus,the rotatable knob interface 150 may be rotated while in either acompressed, a partially compressed, an uncompressed state (and in anyposition in between the states of the rotatable knob interface 150), andthat rotation may be sensed and measured. Similarly, the state of theswitches 220, corresponding respectively to the rotatable knob interface150 being in the “home” or uncompressed state, or in the compressedstate, or in a partially compressed state, may be detected whether ornot the rotatable knob interface 150 is rotationally stationary or beingrotated.

Finally, continuing still with reference to FIG. 2, the rotatable knobinterface 150 has an inner cap 210, and a cover cap 215, as shown. Inoperation, a user physically interacts with cover cap 215, for example,by grasping cover cap 215 and rotating the rotary wheel 230 relative tothe fixed base 231, or by pushing down on cover cap 215 to compress theknob interface and close one or more switches 220. As shown, the innercap 210 is attached, by prongs 211, to a lip provided on the innersurface of vertical ring bearing 225. The cover cap 215 is attached tothe inner cap 210, such that turning the outer cap 215 rotates therotary wheel 230. In other embodiments, mechanisms other than the covercap 215 and/or the inner cap 210 may be utilized to rotate the rotarywheel 230.

FIG. 3 illustrates an exploded view of one example of the rotatable knobinterface 150 of FIG. 2, illustrating the upper side of variouscomponents. With reference to FIG. 3, beginning at the bottom of thefigure, there is shown the upper surface of fixed base 231. The uppersurface is provided with a conductive peripheral ring 235, to be coupledto a reference signal of an input device (e.g., provided by theprocessing system 110 of the electronic device 100) to which therotatable knob interface 150 is to be attached. As shown, the uppersurface also shows an inner conducting ring 232 as well as twoconductive pads 237 and 238. These three conductive regions areconfigured to receive a sensing signal from one or more of the sensorelectrodes 125. Details of these regions, their functions, and how theyinteract with the input device (e.g., the electronic device 100) uponwhich the rotatable knob interface 150 sits, are described in greaterdetail below.

Continuing with reference to FIG. 3, there are also shown the verticalring bearing 225, and a horizontal ring-shaped bearing 226, configuredto slide over the vertical ring bearing 225. In one or more embodiments,because the fixed base 231 has a smaller inner diameter than the rotarywheel 230, there is a ledge at the inner periphery of the fixed base 231upon which the vertical ring bearing 225 may sit. The vertical ringbearing 225 is thus configured to fit inside the inner diameter of thehorizontal ring bearing 226, and rest upon the inner periphery of thefixed base 231. The two bearings thus provide a physical interfacebetween the fixed base 231 and the rotary wheel 230, as noted above,which reduces friction between them as the rotary wheel 230 is moved.

Continuing further with reference to FIG. 3, there are also shown threeswitches 220 provided around the upper surface of rotary wheel 230.Above the switches 220 is shown the inner cap 210, which is configuredto fit inside the vertical ring bearing 225, and be secured to thevertical ring bearing 225 by means of three prongs 211, which, in one ormore embodiments are also placed equidistantly around the inner verticalsurface of the vertical ring bearing 225. As shown, the inner cap 210has a substantially horizontal upper ring, and a lower hollowcylindrical shaped portion. Thus, in one or more embodiments, the outerdiameter of the lower cylindrical shaped portion of the inner cap 210,may fit within an inner diameter of the vertical ring bearing 225, andthen clamp to the bottom surface of the vertical ring bearing 225 by theprongs 211, which slightly protrude under such bottom surface when theinner cap 210 is in the home or uncompressed position. Finally, withreference to FIG. 3, the cover cap 215 is attached to the upper ringportion of the inner cap 210, as shown.

FIGS. 4A through 4C, next described, illustrate the spatialrelationships between coupling electrodes provided on the bottom surfaceof the fixed base 231, respectively connected to correspondingconducting regions on the top surface of the fixed base 231, and thesensor electrodes 125.

FIG. 4A illustrates a view of the underside of the fixed base 231 of therotatable knob interface 150, superimposed over a grid 401 of the sensorelectrodes 125, according to one or more embodiments. The grid 401 maycorrespond to the blackout zone defined by the boundary 155 of FIG. 1.Further, in other embodiments, the grid 401 may correspond to otherconfigurations of the sensor electrodes 125. With reference thereto, thebottom, or underside, of fixed base 231 has three sets of electrodes. Afirst set of electrodes 430, shown as shaded, is a contiguous set ofelectrodes configured to receive a reference signal from one or more ofthe sensor electrodes 125. Three electrodes 410, 420, 411, grouped intothe remaining two sets, are configured to receive a sensing signal fromone or more of the sensor electrodes 125. The second set, includingelectrodes 410 and 411, is configured to sense rotation of the rotatableknob interface 150. The third set, including electrode 420, isconfigured to sense a “click” or the closing of the switches 220, forexample, when the rotatable knob interface is placed in the compressedstate. As shown, each of the coupling electrodes 410, 411 and 420 may atleast partially overlap with, one or more sensor electrodes 125 of thegrid 401. On the other hand, the set of electrodes 430 may each overlapat least portions of multiple sensor electrodes 125 of grid 401, suchthat the set of electrodes 430 acquire a signal from the correspondingreference sensor electrodes 403 (see FIG. 4B) on the grid 401 on theupper surface of the example input device (e.g., the electronic device100), and any effect of a parasitic capacitance from neighboring sensorelectrodes 125 is mitigated. The sensor electrodes 125 of the region 402exclude the sensor electrodes 125 of the region 403. For example, thesensor electrodes 125 of the region 402 include the sensor electrodesdisposed proximate to the coupling electrodes 410, 411, and 420 andexternal to the sensor electrodes of the region 403. This isolation isillustrated in FIG. 4A by two features. First, there is an empty column412 of sensor electrodes to the right of the coupling (or sensing)electrodes 410, 411 and 420 that provides a gap between the coupelectrodes 410, 411 and 420, and the set of electrodes 430. Second, theset of electrodes 430 (full line shading) are each recessed inwardlyrelative to the reference electrodes 403 (shaded with dotted lines inFIG. 4B). The set of electrodes 430 may be recessed by about 1.5 mm toabout 2 mm. However, in other embodiments, the set of electrodes 430 arerecessed by less than about 1.5 mm or more than about 2 mm. Thisrecessing may help the set of electrodes 430 to sense the referenceelectrode signal and minimize sensing the parasitic coupling of nearbysensing signals on the sensor electrodes 125. Further, the recess mayhelp tolerance alignment of the example rotatable knob interface 150 tothe electronic device 100. In other embodiments, including the emptycolumn 412 of sensor electrodes or recessing the electrodes 430 as isdescribed above provides sufficient isolation of the set of electrodes430 to mitigate the effects of the parasitic capacitance fromneighboring sensor electrodes 125 on the set of electrodes 430.

FIG. 4B illustrates the example grid 401 of FIG. 4A divided into twogroups of the sensor electrodes 125, according to one or moreembodiments. Each group of the sensor electrodes 125 may be driven witha different signal. For example, the sensor electrodes 125 in region 403may be driven with a sensing signal while the sensor electrodes 125 inregion 402 are driven by a reference signal. In general, each of thesensor electrodes 125 may be selectively driven with a sensing signal ora reference signal, such as, for example, ground, or other referencesignal. In one or more embodiments, to coordinate the sensor electrodes125 of the grid 401 with the electrodes of the underside of a fixed base231, as shown in FIG. 4A, the grid 401 of the sensor electrodes 125 isarranged as shown in FIG. 4B. Thus, the sensor electrodes 125 of theregion 403 of the grid 401, shaded in FIG. 4B, may be driven with areference signal, and sensor electrodes 125 outside the region 403 maybe driven by with a sensing signal. Accordingly, there is an electricalpairing (e.g., electrical or capacitive coupling) between the undersideof the fixed base 231, and the sensor electrodes 125 of the grid 401.This is illustrated in the superimposed view of FIG. 4C.

FIG. 4C illustrates the underside of fixed base 231 of FIG. 4A aspositioned over the sensor electrodes of the grid 401 of FIG. 4B,according to one or more embodiments. As shown, the coupling (orsensing) electrodes 410, 411 and 420, configured for sensing on therotatable knob interface 150, are aligned with one or more of the sensorelectrodes 125, such that the coupling electrodes 410, 411, and 420 aredriven with a sensing signal via a capacitive coupling between thecoupling electrodes 410, 411, and 420 and the one or more sensorelectrodes 125. In one embodiment, they are driven with the same sensorelectrodes 125. Similarly, the set of electrodes 430, configured forcoupling to a reference signal of the processing system 110, are eachprovided above multiple sensor electrodes 125 of the region 403, to bedriven with a reference signal by the processing system 110. In one ormore embodiments, because the fixed base 231 is stationary, and fixed inposition relative to the input device, the fixed based is first alignedto the sensor electrodes 125 of the input device, as shown, and then, inone or more embodiments, permanently attached to a surface of theelectronic device 100.

Next described, with reference to FIG. 5, is the upper surface of thefixed base 231. With reference thereto, there is shown top perspectiveview 510, which illustrates the positions of electrode regionscorresponding to the sensor electrodes 125 of the regions 402 and 403relative to the top surface of the fixed base 231, according to one ormore embodiments. As shown in the top perspective view, as well as bycomparing bottom surface view 520 with top view 530, the top surface ofthe fixed base 231 is somewhat differently organized than its bottomsurface. To fully appreciate the relative positions of conductive padson the top and bottom surfaces, bottom surface view 520 is also shown,and, as indicated by the curved arrow 521, a corresponding position ofthe top surface is also shown, at top view 530. This top view 530 iswhat would be seen if the fixed base 231 as shown in bottom surface view520 was flipped about a horizontal axis (such that right and left sidesof the fixed base 231 are the same in views 520 and 530, respectively).Continuing with reference to FIG. 5, top view 530 illustrates fourconductive regions, namely inner conductive ring 232 (used to sensewhether the switches are open or closed), the two conductive pads 237and 238 (used to sense rotation) and peripheral ring 235. In one or moreembodiments, each of these is electrically connected by vias to acorresponding conductive region on the bottom surface of fixed base 231.In particular, peripheral ring 235 is electrically connected tocorresponding set of electrodes 430, as noted above, to couple to thesensor electrodes 125 driven with a reference signal; the two conductivepads 237 and 238 are respectively connected to coupling electrodes 410and 411; and inner conductive ring 232, is electrically connected tosensing electrode 420. In some embodiments, as noted above, bothconductive pads 237 and 238, as well as inner conductive ring 232 areconfigured to couple to the sensor electrodes 125 that are driven with asensing signal.

Thus, in the embodiment shown, the top of fixed base 231 has, on itsouter periphery, two small conductive pads 237 and 238 near each other,surrounded by a peripheral ring 235. The peripheral ring 235 receives areference signal, and the two pads 237 and 238 each receive a sensingsignal. The two pads are used to sense rotation. A second, the innerconductive ring 232 inside of the peripheral ring 235 is configured toalso receive a sensing signal to sense whether the switches are closed.The closing of the switches may also be referred to as a “click” fromthe sound they make when they close.

FIG. 6A illustrates exploded view 601 and collapsed view 603 of theexample fixed base 231 and example vertical ring bearing 225 andhorizontal ring bearing 226 (e.g., plastic bearing) shown in FIG. 3. Asthese elements have been previously described, they are not describedagain here. What is noted is, in one or more embodiments, as is shown incollapsed view 603, horizontal ring bearing 226 has a smooth surface ontop of which the rotary wheel 230 can rest, and vertical ring bearing225 has a smooth outer cylindrical structure around which the rotarywheel 230 can turn.

FIG. 6B illustrates the respective exploded view 610 and collapsed view603 of the of the example fixed base 231 and bearings 225, 226 shown inFIG. 6A, with the addition of the example rotary wheel 230 of FIG. 3provided on top of an example flat ring-shaped bearing 226. As shown,the vertical ring bearing 225 has a larger height than that of therotary wheel 230, such that it protrudes above the rotary wheel 230.Visible in each of exploded view 610 and collapsed view 603, are threesets of pads 221 provided on a top surface of the rotary wheel 230 forconnection to the set of switches (not shown). This is described ingreater detail below, after the organization of the bottom surface ofthe rotary wheel 230 is described.

FIG. 7A illustrates a detailed bottom view of the rotary wheel 230 ofFIG. 3. With reference thereto, as in the case of the top surface of thefixed base, there are essentially two ring shaped structures. An outerperipheral ring 701 which comprises alternating first conductive regions710 and non-conductive regions 720, and an inner ring which comprises asingle connected second inner ring (e.g., conductive region) 730,according to one or more embodiments. Additionally, the ring-shapedregion 702, provided between the outer peripheral ring 701 and the innerring 730, is also non-conductive. In one or more embodiments, firstconductive regions 710 are used to sense rotation, and inner ring 730 isused to sense “click.”

FIG. 7B illustrates a detailed top view of the example rotary wheel ofFIG. 3. The view of FIG. 7B corresponds to the view of the top surfaceof rotary wheel 230 shown in FIG. 6B that illustrates three sets of pads221 which each respectively connect to a switch. The top view of FIG. 7Bis drawn transparently, to show the underlying conducting rings to whicheach set of pads 221 is respectively coupled, as well as the otherconductive regions on the bottom and top surfaces of the fixed base 231,previously described. These include, as shown here via the transparency,and as shown in FIG. 4A, on the bottom surface of the fixed base 231,the coupling electrodes 410, 420 and 411 and the set of electrodes 430that is coupled to a reference signal of the processing system 110; andon the top surface of the fixed base 231, a portion of the peripheralring 235, and the conductive pads 237 and 238.

The conductive regions 710 of FIG. 7A, as well as the conductive pads237 and 238, and the peripheral ring 235 of FIG. 7B, may be made ofknown conductors, such as, for example, copper, silver, gold, aluminum,indium tin oxide, or other conductors, or, for example, various alloysof any of those, with each other, or with different elements orcompounds. In one embodiment, the non-conductive regions 720 may beregions of a printed circuit board or substrate on which no metal isdeposited, and thus be made of epoxy plastic and fiberglass, forexample. In another embodiment, the non-conductive regions 720 may beformed by depositing an insulating layer such as, for example, a silicondioxide (SiO₂) layer.

As shown in FIG. 7B, there are two ring shaped conductive regions,namely the outer ring region (e.g., the conducting ring 712) and theinner ring region 732, for example, provided just under the surface ofthe top side of the rotary wheel 230. The outer ring region (e.g., theconducting ring 712) is electrically connected to each of the firstconductive regions 710 on the bottom side of the rotary wheel 230, asshown in FIG. 7A, by vias (not shown). Similarly, the inner ring region732, provided on the inner periphery of the top side of the rotary wheel230, is electrically connected to the second conductive inner ringregion 730 on the bottom side of the rotary wheel 230, also shown inFIG. 7A, by vias (not shown). Additionally, in the depicted example ofFIG. 7B, while the positions of the three sets of pads 221 to which thethree switches 220 are to be connected are shown, the switches are notshown. Thus, when the switches 220 are closed, by a user pushing down onthe cover cap 215 (shown in FIGS. 2 and 3) until the switches 220 make aclicking sound or an equivalent other indication, the inner portion ofeach pad is electrically connected to the outer portion of each pad,which causes the regions corresponding to the conducting rings 712 and732 to be electrically connected. This also may cause, with reference toFIG. 7A, the respective first conductive regions 710 to be connected tothe inner ring region (e.g., a second conductive region) 732. It isnoted that there may be more or less switches, and corresponding sets ofswitch pads to which they connect, in alternate embodiments. The pads221 may be referred to as switch pads, and may be placed equidistantlyaround the rotary wheel 230, as shown. In some embodiments the switches220 may have more than two states, and thus have more positions than“compressed” or closed, and “uncompressed” or open.” In suchembodiments, the switches 220 may have one or more intermediate statesbetween “compressed” and “uncompressed”, and a user may push down on thecover cap 215 to move between an “uncompressed” or fully open state, andeach of the intermediate states and the fully closed state. In suchembodiments, each position of the switch 220 may be sensed, such as, forexample, by signal strength of the electrical coupling at each state ofthe switch.

Given the descriptions above of the respective top and bottom surfacesof each of fixed base 231 and rotary wheel 230, the dashed arrows 801and 802 of FIG. 8 illustrate the electrical coupling between the topsurface of the fixed base 231 and the bottom surface of rotary wheel230. The top surface of the fixed base 231 faces the bottom surface ofthe rotary wheel 230 in the assembled rotary knob interface 150, whenthe rotary wheel 230 sits above the fixed base 231. With referencethereto, dashed arrow 801 depicts the electrical coupling between theinner conductive ring 232 of the top surface of the fixed base 231 andthe inner ring 730 of the bottom surface of the example rotary wheel230. Additionally, dashed arrow 802 depicts the electrical couplingbetween peripheral ring 235 of the top surface of the example fixed base231, which includes conductive pads 237 and 238, and the variousconductive regions 710 of the outer peripheral ring 701 of the bottomsurface of the example rotary wheel 230. As noted above, the regions 720of the outer peripheral ring 701 of the bottom surface of the rotarywheel 230 are non-conductive. Further, the non-conductive divider ring702 is non-conductive, and is provided between the outer peripheral ring701 and the inner ring 730.

As shown in FIG. 8, when the rotary wheel 230 sits above the fixed base231 (with the horizontal bearing between them), there may be variouselectrical couplings between their respective peripheral ring regions.The peripheral ring 235 is coupled to a reference signal driven by theprocessing system 110 via the set of electrodes 430. Further, theperipheral ring 235 is capacitively coupled to one or more of theconductive regions 710 of the underside rotary wheel 230. Whether one orboth of the conductive pads 237, 238 are coupled to the conductive pads710 of the underside of the rotary wheel 230 depends upon the relativerotational position of the rotary wheel 230 and the fixed base 231.

To sense rotation, the two conductive pads 237 and 238 on the topsurface of fixed base 231 are coupled to sensor electrode 125 that arerespectively driven with sensing signals by the processing system 110.As noted above with reference to FIG. 4A, the conductive pads 237 and238 on the top surface of fixed base 231 are respectively electricallyconnected by vias with the coupling electrodes 410 and 411 provided onthe bottom surface of the fixed base 231. In turn, the couplingelectrodes 410 and 411 are coupled to corresponding sensor electrodes125 that are driven with sensing signals, as shown, for example, in FIG.4C. By driving the sensor electrodes 125 that are respectively coupledto the fixed base coupling electrodes 410 and 411 with sensing signals,the resulting signals that are received by those sensor electrodes varyas a function of the capacitive coupling of each of the two conductivepads 237 and 238 on the top surface of fixed base 231 with the array ofconductive region 710 and non-conductive regions 720 on the bottomsurface of the rotary wheel 230.

FIGS. 9A through 14, described below, illustrate various enhancementsto, or alternate functionalities of, the rotatable knob interfacedescribed above with reference to FIGS. 1-8. It is noted that in one ormore embodiments, some, or many, of the enhancements and alternatefunctionalities may be combined in any given example device.

FIGS. 9A and 9B illustrate an alternate approach to sensing click, ormechanical response functionality, of a rotatable electronic device. Inthis example approach, click sensing may be facilitated on the fixedbase of the rotary electronic device. This is in contrast to theapproach described above with reference to FIG. 2, where the rotarywheel 230 is provided with three example switches 220 on its uppersurface. When, in the example of FIG. 2, switches 220 are closed, thetwo conducting ring regions 712 and 732, as shown in FIG. 7B, areelectrically connected, which is then sensed by the processing system110.

In embodiments where the rotatable electronic device does not include acentral hole in the fixed base, switches that effect click sensing donot need to be capacitively routed to the rotary wheel. As a result,these switches may be provided on the fixed base. FIG. 9A showsunderside of an alternate fixed base 932 provided with a click sensingpad 920. FIG. 9B, in which the top view of the alternate fixed base 932is depicted, shows a dome switch 950 that connects the grounded region933 to the click sensing pad 920. Grounded region 933 is conductive, andthus if multiple electrodes on a surface of an input device are coupledto it, those electrodes become electrically coupled to each other. Thisfact is leveraged in the example shift detection methods described belowin connection with FIGS. 12A, 12B and 13. It is here noted thatalternate fixed base 932 allows for an increased signal for sensing theclick and reduces the complexity of routing the click functionality tothe rotary wheel. FIGS. 9A and 9B also show two kidney shaped apertures939 on either side of fixed base 932. Apertures 939 may improve signalintegrity in the following way. As shown in FIG. 9A and in FIG. 4B,fixed base 932 may be provided above a group of sensor electrodes 402 onan upper surface of an example input device that are driven with asensing signal. Additionally, above fixed base 932 may be provided therotary wheel 230, shown in FIGS. 7A and 7B. On the bottom side of therotary wheel 230, as further shown in FIG. 7A, there may be providedconductive regions 710. Thus, fixed base 932 is “sandwiched” in betweensensor electrodes 402 on an upper surface of an input device, and theconductive regions 710 on the bottom side of the rotary wheel 230.Apertures 939 on fixed base 932 may reduce parasitic capacitance betweenthe conductive regions 710 on the underside of rotary wheel 230 and theelectrodes 402 on the input device. Capacitance may be calculated basedupon the overlapping areas of the two regions of interest, the distancebetween them, and the dielectric between the two regions. Apertures 939introduce air, which has a dielectric constant of 1, as the dielectricmedium in between sensing electrodes 402 and conductive regions 710.This is instead of plastic, or, for example, FR4 (a composite materialmade of woven fiberglass cloth with an epoxy resin binder that is flameresistant), which are materials an example fixed base 932 may be madeof. Because plastic and FR4 each have a significantly higher dielectricconstant than air, the air gap provided by apertures 939 may thus reducethe parasitic capacitance between the conductive regions 710 on thebottom side of the rotary wheel and sensing electrodes 402.

In alternate examples, apertures 939 may have different shapes, or maynot be used at all.

FIG. 10 illustrates a bottom view of an example fixed base 1031. Examplefixed base 1031 is similar to fixed base 231 of FIG. 4A, but thegrounded region 936 is somewhat larger, and has a different shape. FIG.10 also depicts outlines 906 drawn around regions of the underside offixed base 1031 to be attached to a display panel (not shown), with aconductive adhesive, according to one or more embodiments. As analternative to attaching the fixed base to the display panel using anon-conductive adhesive, conductive adhesives may be used for selectedregions to improve the signal by increasing the coupling of the fixedbase sensing pads 410, 411, 420, and fixed base grounded region 936,respectively, to the touch pixels of the display panel. The displaypanel to which the underside of fixed base 1031 may be attached may bedisplay panel 120 of FIG. 1, for example. With reference to FIG. 10, inone or more embodiments, the outlined regions 906 may be attached to thedisplay panel with a conductive adhesive while other regions may beattached using a non-conductive adhesive. Conductive adhesives may beisotropic or anisotropic, and can be any suitable electricallyconductive adhesives.

FIG. 11 depicts an example conductive structure 959 that may be used inplace of a rotary wheel and thin bearing, according to one or moreembodiments. As an alternative to the thin bearing 226 described in FIG.6A, conductive bearings may be used, such as, for example, those made ofconductive PTFE (polytetrafluoroethylene). In such alternateembodiments, the rotary wheel may not be needed, and, as shown in FIG.11, there may be a combination bearing and rotatable element 959 used inits place. Such alternate embodiments allow for a much thicker bearing,for example on the order of 1-2 mm thick, which can provide a strongersignal due to the increased conductivity of the bearing. It is notedthat conductive PTFE may be formed by, for example, infusing carbon intoPTFE to increase its conductivity. Thus, instead of using both the thinbearing 226 as shown in FIG. 6A, and the example rotary wheel 230 withalternating conductive 710 and nonconductive 720 regions as depicted inFIGS. 7A and 7B, conductive structure 959 shown in FIG. 11 may be used.Exemplary conductive structure 959 has, as shown, a central ring 961from which several peripheral regions 960 protrude. In the depictedexample there are four peripheral regions, spaced at 90 degree intervalsaround a central ring 961. In other examples, greater, or fewer,peripheral regions may be used. Peripheral regions 960 have a longdimension that is tangential to the inner ring, as shown, and theyalternatively pass over the conductive pads provided on the top of thefixed base 932. For example, the alternate fixed base 932 illustrated inFIGS. 9A and 9B may be used. Thus, peripheral regions 960 of theconductive structure 959 alternatively couple to sensing regions 925(not shown in FIG. 11, but shown in FIG. 9B at the top left) and 926, aswell as grounded region 933 of the top of fixed base 932. As a result,as the conductive structure 959 is rotated, there are changes in thecapacitive coupling between sensing regions 925, 926 and grounded region933. Since structure 959 is itself conductive, the capacitive couplingis an electrical connection if, as in this example, there is no bearingprovided in between the top of fixed base 932 and conductive structure959. It is also noted that, given the spacing of peripheral regions 960,conductive region 963 of fixed base 932 is always coupled or connectedto conductive structure 959. As conductive structure 959 rotates,however, the capacitive coupling between peripheral regions 960 andsensing regions 925 (not shown) and 926 change. In one or moreembodiments, these changes may be used to determine the rotationalorientation of the conductive structure 959, and thus of the rotationalknob interface. As noted, in one or more embodiments, the conductivestructure 959 also acts as a bearing, but now may be considerablythicker than, for example, the thin bearing 226 described above.

As noted, the fixed base 932 of FIG. 11 is the same as the example fixedbase 932 of FIGS. 9A and 9B, described above. As shown in FIG. 9A, aclick sensing pad 920 is provided on the underside of fixed base 932.This click sensing pad 920 is connected to switch pads 951 on the upperside of fixed base 932. Similarly, grounded region 933 is connected toswitch pads 952 on the upper side of fixed base 932. A dome switch (notshown) may be connected between switch pads 951 and 952, e.g., domeswitch 950 shown in FIG. 9B, to sense click.

Next described, with reference to FIGS. 12A through 13, are two examplemethods for detecting a shift of the rotatable knob interface relativeto the surface of the input device. A shift in knob base can indicate afailure of the rotatable knob interface. Thus, detecting such a shiftmay be used to determine failure of the rotatable knob interface.

A first example method of shift detection is described with reference toFIGS. 12A and 12B. FIGS. 12A and 12B illustrate, from a point of viewthat is underneath the display panel of the input device, a set ofelectrodes 403 of an example display panel that are provided underneatha grounded region 936 on the underside of a fixed base 1231 of anexample rotatable knob interface, according to one or more embodiments.As noted above, grounded region 936 is so-called because the electrodesof the display panel over which it is provided are, during an inputsensing interval, driven with a reference signal. However, in the firstexample method of shift detection, this is modified, and not all of theelectrodes of the display panel that lie under the grounded region aredriven with the reference signal of a regular input sensing interval. Asis illustrated in FIG. 12A, in a first pre-defined time interval, all ofthe electrodes 403 that couple to grounded region 936 are driven with areference signal. At a later time, shown in FIG. 12B, during a secondpre-defined time interval, a first subset of the electrodes 403, forexample half of electrodes 403, in a first subset region 404 (surroundedby a dashed line boundary in FIG. 12B), may be driven by a sensingwaveform, and the remaining electrodes of the set of electrodes 403,e.g., those in a second subset region 405, may be driven by thereference signal.

The configuration of FIG. 12A, where all of electrodes 403 lying underthe grounded region 936 of the fixed base 1231 are driven by thereference signal, is, as described above, the normal scheme used duringinput sensing, e.g., during sensing of a rotation of the rotatable knobinterface. However, the configuration of FIG. 12B occurs during aspecific time interval outside of the normal sensing scheme, e.g., notduring a standard input sensing interval, where, for example, half ofthe electrodes 403, those in first subset region 404, are driven by asensing waveform. Because the entire grounded region 936 is electricallyconnected, during the second pre-determined time interval the electrodesin first subset region 404, although driven by a sensing signal, arealso grounded, as both first subset region 404 and second subset region405 remain connected via grounded region 936 of the fixed base 1231. Inan embodiment, an analog to digital converter (ADC) may be used to sensecapacitance on electrodes in first subset region 404 that are drivenwith a sensing signal. In such an embodiment, for a given electrode infirst subset region 404, a reading on the ADC will change as a functionof its ground loading. In some embodiments, the greater the groundloading, the lower the signal on the ADC. Thus, in such embodiments,when the rotatable knob interface is in its correct place, above thefirst subset region 404, the electrodes of first subset region 404 willsee a certain value on a connected ADC that reflects grounded loadingvia grounded region 936. However, if the rotatable knob interface slips,and grounded region 936 of fixed base 1231 is no longer above one ormore electrodes of first subset region 404, a higher value on an ADCconnected to that electrode will be seen. In an embodiment, this higherADC value may be used to detect a slip, or translation, of the fixedbase 1231, and thus the rotatable knob interface. Thus, in anembodiment, ADC values of the electrodes in first subset region betweensuccessive second pre-defined intervals may be compared to determine ashift. Alternatively, a given reading for an electrode in a secondpre-defined interval may be compared to an ADC value for that electrodeat manufacture, following the fixed base being attached to the displaypanel in its intended position, to determine if the fixed base 1231 hasshifted. As noted, the second pre-defined interval occurs outside ofnormal input sensing, and thus additional time may need to be allocatedfor shift detection within an input sensing scheme.

In alternate embodiments, the set of electrodes 403 may be divided intonon-equal subsets, where the number of electrodes in first subset region404 is less than the number of electrodes in second subset region 405.For example, the number of electrodes in first subset region 404 may besome fraction of the total number of electrodes in set of electrodes403, such as, for example, ⅓, ¼ or some other fractional value less than1.

In a second example method of shift detection, which is a variation ofthe first example method, the same principle of connected ADC valuechanging as a result of ground loading may be utilized in a differentmanner. In the second example method a first subset region of electrodeslying under grounded region 936 may be driven with a sensing signal evenduring normal input sensing. This is illustrated in FIG. 13. Withreference thereto, FIG. 13 shows a first subset region 406 of electrodesof the grid of electrodes 125 of the display panel. First subset region406 of electrodes (shown with a dashed line boundary in FIG. 13) areprovided underneath the grounded region 936 of the fixed base 1231. Inan embodiment, a previous baseline state of a resulting signal receivedon the electrodes in subset region 406 may be compared to a currentlyacquired resulting signal to determine if any shift of the fixed basehas occurred. In one or more embodiments, as was the case for the firstexample method, the resulting signal may be measured using the value onan ADC connected to an electrode, and a change in ADC value may be usedto detect shift of the fixed base 1231, and thus of the rotatable knobinterface, may be determined from a change in the value on a connectedADC for the electrodes in first subset region 406.

In an embodiment, for the example method illustrated in FIG. 13, the setof electrodes 403 that are coupled to grounded region 936 may be dividedinto non-equal subsets, where the number of electrodes in the firstsubset region 406, which receive the sensing signal during an inputsensing interval, is less than the number of electrodes in second subsetregion 405. For example, the number of electrodes in first subset region406 may be some fraction, less than ½, of the total number of electrodesin the set of electrodes 403. For example, it may be 1/10th of the totalnumber of electrodes that are in the set of electrodes 403. Or, forexample, it may be 20%, or 15%, of the total number of electrodes in setof electrodes 403, or any other fractional value between 0 and ½.

Because in the second example method of shift detection, the electrodesin first subset region 406 are always driven by sensing signals duringregular input sensing intervals, the comparison may be made between tworegular (e.g., successive) input sensing intervals, and no additionaltime interval need be added to the input sensing schema for shiftdetection.

FIG. 14 is a process flow chart illustrating a method 1400 for detectingshift of a fixed base of an electronic interface, for example arotatable knob interface, on an example electronic device. The methodhas two stages, respectively corresponding to the two examplesillustrated in FIGS. 12A and 12B respectively, described above. Asnoted, detecting knob shift is one mechanism of failure.

Method 1400 includes blocks 1410 through 1440. In alternate embodiments,method 1400 may have more, or fewer, blocks. Method 1400 begins at block1410, where, during a first time period, a reference signal is providedto first and second sets of electrodes of an input device that arecapacitively coupled to a single conductive region on the underside of afixed base of a knob interface. The fixed base is provided on a surfaceof an input device (e.g., the electronic device 100). For example, theconductive region may be grounded region 936 shown in FIGS. 12A and 12B.

From block 1410, method 1400 proceeds to block 1420, where, during asecond time period, a sensing signal is provided to the first set ofelectrodes, and the reference signal to the second set of electrodes.For example, the first set of electrodes may be the electrodes in region404 of FIG. 12B, and the second set of electrodes may be the electrodesin region 405 of FIG. 12B, all of which are coupled to conductive region936 on the fixed base 1231.

From block 1420, method 1400 proceeds to block 1430, where, during thesecond time period, a resulting signal on the first set of electrodes isreceived. As noted above, the resulting signal is the same signal usedto drive the first set of electrodes, except that when it is measured itmay have been modified by the relative positions of the fixed base 1231and the input device.

From block 1430, method 1400 proceeds to block 1440, where, based atleast in part on the resulting signal values on the first set ofelectrodes obtained during the second time period, and a previousbaseline state for the first set of electrodes, a translation of theknob interface on the surface of the input device is determined. In oneor more embodiments, this determination may be performed by firmwarestored in a memory of the input device. Method 1400 may terminate atblock 1440, or, as shown in FIG. 14, it may be repeated, and thus fromblock 1440, method 1400 may return to block 1410. In one or moreembodiments, the baseline state may be pre-stored, e.g., atmanufacturing, or, for example, may be a set of resulting signal valuesobtained during a prior second time period of a prior instance of method1400.

Thus, the embodiments and examples set forth herein were presented inorder to best explain the embodiments in accordance with the presenttechnology and its particular application and to thereby enable thoseskilled in the art to make and use the disclosure. However, thoseskilled in the art will recognize that the foregoing description andexamples have been presented for the purposes of illustration andexample only. The description as set forth is not intended to beexhaustive or to limit the disclosure to the precise form disclosed.

In view of the foregoing, the scope of the present disclosure isdetermined by the claims that follow.

1. A sensing system, comprising: a display panel comprising sensorelectrodes; a rotatable electronic device disposed over the displaypanel, the rotatable electronic device comprising: a fixed base disposedover the display panel, the fixed base comprising a first region, aclick sensing pad, and a switch disposed between the first region andthe click sensing pad; and a rotatable knob disposed over the fixedbase; and a processing system configured to: sense a click based on therotatable knob being pressed such that the switch couples the firstregion to the click sensing pad.
 2. The sensing system according toclaim 1, wherein the switch is a dome switch.
 3. The sensing systemaccording to claim 1, wherein the first region is grounded.
 4. Thesensing system according to claim 1, wherein the fixed base includesapertures configured to reduce parasitic capacitance between conductiveregions on an underside of the rotatable knob and sensor electrodes ofthe display panel.
 5. The sensing system according to claim 1, whereinthe first region of the fixed base is attached to the display panel viaa conductive adhesive.
 6. The sensing system according to claim 5,wherein other regions of the fixed base are attached to the displaypanel via a non-conductive adhesive.
 7. The sensing system according toclaim 1, wherein the click sensing pad is disposed on an underside ofthe fixed base, wherein the switch is disposed on an upper side of thefixed base, and wherein the click sensing pad is connected to one ormore switch pads on the upper side of the fixed base.
 8. The sensingsystem according to claim 1, wherein the rotatable knob comprises arotary wheel and a bearing.
 9. The sensing system according to claim 8,wherein the bearing is made of conductive polytetrafluoroethylene(PTFE).
 10. The sensing system according to claim 1, wherein therotatable knob comprises a combination bearing and rotatable elementhaving a central ring and a plurality of protruding peripheral regions.11. The sensing system according to claim 1, wherein the combinationbearing and rotatable element is conductive and has a thickness in therange of 1-2 mm.
 12. A rotatable electronic device for use with adisplay panel, the rotatable electronic device comprising: a fixed basedisposed over the display panel, the fixed base comprising a firstregion, a click sensing pad, and a switch disposed between the firstregion and the click sensing pad; and a rotatable knob disposed over thefixed base; wherein the switch is configured such that pressing on therotatable knob couples the first region to the click sensing pad. 13.The rotatable electronic device according to claim 12, wherein theswitch is a dome switch.
 14. The rotatable electronic device accordingto claim 12, wherein the first region is grounded.
 15. The rotatableelectronic device according to claim 12, wherein the fixed base includesapertures configured to reduce parasitic capacitance between conductiveregions on an underside of the rotatable knob and sensor electrodes ofthe display panel.
 16. The rotatable electronic device according toclaim 12, wherein the click sensing pad is disposed on an underside ofthe fixed base, wherein the switch is disposed on an upper side of thefixed base, and wherein the click sensing pad is connected to one ormore switch pads on the upper side of the fixed base.
 17. The rotatableelectronic device according to claim 12, wherein the rotatable knobcomprises a rotary wheel and a bearing.
 18. The rotatable electronicdevice according to claim 12, wherein the rotatable knob comprises acombination bearing and rotatable element having a central ring and aplurality of protruding peripheral regions.
 19. A method for clicksensing using a rotatable electronic device, comprising: providing arotatable electronic device disposed over a display panel, the rotatableelectronic device comprising a fixed base disposed over the displaypanel and a rotatable knob disposed over the fixed base, wherein thefixed base comprises a first region, a click sensing pad, and a switchdisposed between the first region and the click sensing pad; andsensing, by a processing system, a click based on the rotatable knobbeing pressed such that the switch couples the first region to the clicksensing pad.
 20. The method according to claim 19, wherein the switch isa dome switch, and the first region is grounded.